From Scientific American:
There’s new hope for the more than 7 million American women (and their partners) who long for a child and are plagued by infertility. Australian researchers have developed a method for screening embryos created through in vitro fertilization (IVF) to select the ones that have the best shot of developing into healthy babies. The process, reported in Human Reproduction, utilizes DNA fingerprinting (an assessment of active genes in a given cell) to boost the success rate of IVF and lower the chances of risky multiple births by identifying which of several five-day-old embryos are most likely to result in pregnancy The new method, which will replace unproved alternatives such as choosing embryos based on their shape, is likely to up the success of women becoming pregnant and lower their chances of having multiple births.
In IVF, eggs from a woman are fertilized by male sperm in a Petri dish and allowed to grow for five days until they become blastocysts consisting of about 50 to 65 cells. Because there are currently no precise methods for selecting viable embryos, couples typically choose to implant multiple blastocysts to enhance their chances of conceiving, which may also result in multiple pregnancies. According to the study, about 42 percent of women who go through in vitro fertilization today become pregnant; of those, 32 percent give birth to twins, triplets or even more babies, according to the Centers for Prevention and Disease Control.